Hi Jim, hope you are doing fine.my tucano has a mag.52 2c,and my tank is higher than it should be,so you may have flooding issues at start up.It is very annoying having to get it started when you need a flying buddy to hold the plane upside down until it runs for the first flt of the day.I usually allow a 1/4" from the back of the spinner to the ont front of the cowling, then i used blue scotch tape and mark on the outside of the fuse against the back of the cowling.if it lines up you should secure the cowling as you prefer.I use scrap mounting blocks and glue them around the face of the firewall and shaping them around to the edge of the firewall.this way once you measure from the c/l of the mounting blocks to the edge of the blue tape on the fuse you can drill and secure the cowling that will last indefinetely.I did not make any adjustments to the engine mount/firewall.I did invest in a 2 1/2" alum spinner.the one i got with my arf lasted only 3 flts b-4 it came apart.If i have missed anything pls let me know. I know this minor issues can drive you crazy,but on a happy note this plane is superb!!! very fast,fully aerobatic,great vertical performance,I have done 6 aileron rolls continously in this model,and it does this better than my .46 stick,also the recommended control surface throws are right on the money,use them for first trials and go from there.i almost forgot with a magnum.52 it was a little too nose heavy,so i had to add a short strip of lead weight to the bottom of the horizontal stab,and painted it red to hide it. happy landings!