'Aged' Stout questions

Posted this on Recipe Advice forum, but trying to gain max traction, really!

So, my brother-in-law and I have been discussing a "Barrel-aged" stout recipe - except we don't have a barrel, we plan to age it on woodchips used to age home distilled Bourbon.

Recipe is similar to my Guinness Clone recipe:

5kg Base Malt (Probably Bairds Pale)

2kg Flaked Barley

500gms of Roasted Barley.

Med and/or Dark Crystal somewhere in there too.

So a few of questions:

1, we want it a bit sweeter to counter-act the higher alcohol, but how much Crystal is too much?

2, can we go more Roasted Barley for this recipe despite the SRM it shows? I used 500gms in my Guinness Clone and that was 10%

3,what amount of woodchips should we use?  200gms?  500 gms?  Does it even matter?

4, since I'm currently brewing a Guinness Clone using S04, would it be worth using the whole yeast cake from that to pitch this beer considering the higher gravity we expect (around a 1.080) or will that be too much?  Will that cause a horrible hotness to the beer?  Even still, won't that age out on the chips?

Any ideas, thoughts or advice would be very much appreciated - doing this next weekend.