PS, Wrangler, if that's your first covering job- you are a natural. It is a tough skill to master, especially on light (flimsy) structures like the belly of this bad boy. You pull too hard here, it wrinkles there because the structure gives so easily. So beautiful job, kudos, dude! Go easy on yourself, the first few won't be perfect, and neither will the last!!!!
The most useful hint that I got for covering was tack at low temperature and go for a light even stretch with these tack points before shrinking at hi temp. You need to let the iron warm up a while so that it is evenly andconsistently hot. You do well to use a low heat first, ~1/3 of most irons' knobs, testing with scraps to set the iron temp to where it just tacks the covering to a chunk of balsa, so its removed with the iron and tweezers if you need to reposition it. Then you begin by tacking the diagonal points at light tension (fingers only) front left, rear right, front right, rear left, and then proceed to do the 1/2 way points between these diagonal corner tacks on all 4 sides, in opposition- front center, then rear center, then RHS center, then LHS center. Then you do the points 1/2 way between these, again in opposition, etc until your tack marks are <1" apart. Finally, turn up the heat a tad, say ~1/2 the knob range and iron the periphery completely and rub lightly right behind the iron with a cloth or glove to spread& seat the glue while its hot. Last comes shrink, but it should be almost wrinkle free before you crank up the heat for shrinking... or it will just sag in the sun if you have to shrink it smooth. If you get sags in the sun, they come out with an iron, forever. This ARF came with a lot of sun sagging as you probably noticed!

I prefer Ultracote a.k.a. Oracover because the glue and color are separate. This allows you to 'redo' stuff without getting the color peeling off when you remove a corner or other tack point to reset and remove a wrinkle.