Various questions about endless Ishapore 2A restoration

So a while ago I picked up an Ishapore 2A for about $350. I'm quite happy I did as they're much more now. It was newly-imported and unfired, it seems. But the fore stock was uh. Bad. So mushy and soft with oil that the lugs just crumbled when I was trying to chisel them out. So I recently bought a new stock and I have a handful of questions on it.

First being that the new fore stock is too long at the rear. I need to remove considerable material on the back of the stock for it to fit my action. It also may be very slightly warped but I'm unsure. Right now my concern is removing the plate at the back of the stock, which appears to be held in by a cut-off screw. Can't get any considerable purchase on said screw and wondering i I need to just drill it out or if there's a trick to it.

Second question being if anyone knows of good ways to remove oil from stocks so I could repurpose the already fitted fore stock. The biggest issue is that the lugs were beaten to dust and I chiseled those out already. Heat methods like the garbage bag trick don't work too great for me as I live in Minnesota and half the year don't have sunlight.

Third, I'm wondering if anyone has the dimensions of the stock. One concern of mine has been not knowing the dimensions of the recoil draws and I've been hesitant to go ahead and attempt the repair on my old stock because of that. If anyone has any info that could help me on the woodworking aspect I'd be really grateful. I also wonder how the screw collar in the stock is retained because I need one for my new stock i'm trying to fit.

I've searched on these matters as much as I can and haven't found answers to a lot of this, so I appreciate any help I can get. Thanks to everybody!

Soak it in Dollar Store clear ammonia for a while and watch the grease, oil and crud come off. Works like a charm. I use a Scotchbrite pad and a toothbrush to help it along. There is an article here by Peter Laidler on patching the draws. Read it three times and then dive in carefully. It's tedious and time consuming but necessary in your case if I read your post right.

Photos would be very helpful.

If you are installing an MK III stock on this rifle, it should fit the action with only minor fitting. Sounds like you may have a No 4 stock which is a completely different rifle.

Cringing at the image of chiseling anything out of the stock.

Garbage bag trick should work anywhere so long as you have a windshield and can point the vehicle into the sun. Winter can be challenging. Putting the stock near a heat source is a fair substitute and since the forestocks are short, they would fit in an oven although great care should be taken to not overheat the stock using this method. After getting most of the oil out with heat, Citristrip in arasol form should do the trick for the last bits.